New research could reduce milk spoilage, extending shelf life

The moment you place a carton, jug or bag of milk in your grocery shopping cart, you enter a race against the date stamped on the side — can you drink all this milk before it goes bad?

Usually, you have about a week to drink it up, but recently science has come up with a new model for dramatically reducing milk spoilage that could extend this time by up to a few weeks.

Researchers at Cornell University in New York have created a predictive model that looks at the presence of spore-forming bacteria to gauge milk spoilage levels.

“Putting dates on milk cartons is a big issue, because consumers often discard the milk if it is past the sell-by date,” said Martin Wiedmann, senior author of the recent study. “Often there is little science behind those dates, as they are experience-based guesses. The goal of this research was to put good science to use, reduce food waste and reduce milk spoilage.”

It works like this: Some spore-forming bacteria, like Paenibacillus and Viridibacillus, can survive the pasteurization and sanitation processes. The resilient bacteria, which are commonly found throughout the dairy production chain, spoil milk with off-flavors and curdling. The research team found that controlling temperature helped control populations of these bacteria. Their model shows that only 9% of milk kept at 39.2°F was spoiled after 21 days, compared with 66% that was refrigerated at 42.8°F.

“This is a considerable problem,” said Nicole Martin, research support specialist from Cornell. “If we can reduce the spoilage from spore-forming bacteria — by reducing their presence and by controlling their outgrowth — we can see the shelf life for milk improve from two weeks to perhaps a month.”

The research team envisions a future with no date stamps — perhaps, instead, a barcode that provides a blockchain-like traceback showing the milk’s production history and a more accurate best-by date.

“This is the foundational work that could get us there, where consumers could manage their food inventory in the fridge,” Wiedmann said.